Electrical connector



Feb. 23, 1943. A. J. SCHMITT 2,312,002

ELECTRICAL CONNECTOR Filed Dec. 5, 1940 V 5a J3 fla Xga 9 I 2%/ `23a 22 I. Y E

' Z'1 J7 z 5 a 0 J"762 50 55 9J-70 @e @j +3 9 f@ [Q l gg 22 119 70 Qa Q13 L//u/wru Patched Feb. '23, 1943 UNITED STATES PATENT OFFICE ELECTRICAL CONNECTOR Arthur J. schmitt, Chicago, 1u.

Application December 5, 1940, Serial No. 368,658 i (CL 17H28) 4 Claims.

This invention relates to electrical connectors more particularly of the so-called automatic safety grounding class in which the separation of electrodes causes certain of them to be electrically grounded and, conversely, interengagement of electrodes breaks the grounding contact.

A useful application of such a connector is on aircraft for automatically grounding the magneto to the engine frame when the device 'is disconnected, thus eliminating the danger of injury to personnel which might otherwise be caused by accidental starting oi' an engine should the propeller be moved during inspection or while minor repairs are being made.

The present invention aims to provide an improved connector of this class more particularly for a three wire system which can be produced in large quantities at relatively low cost by reason of simplicity of construction and ease of assembly, and which at the same time is sturdy and unfailing in operation, so as to be especially adapted for use where maximum safety is imperative.

A further object of the invention is to provide an insulating connector core for a connector of this class which is readily removable from its shell and which may be assembled with either a receptacle type shell or a plug type shell, interchangeably, thus enhancing the adaptability and I versatility of the connector.

Other objects and advantages will` be apparent from the following description, taken together with the accompanying drawing, in which- Figure 1 is an exploded view showing shell parts with which my improved connector may be associated;

Figure 2 is an enlarged sectional view of one form of assembly of my improved connector with the shell parts shown in Fig. 1;

Figure 3 is a cross-section taken on the line 3-3 of Fig. 2;

Figure 4 is a side elevational view, on the scale of Fig. 1, of a preferred form of insulating core for my improved connector;

Figure 5 is `a dissociated somewhat diagrammatic viewof the connector core contact members and associated prongs of the circuit continuing element. with exemplary wiring therefor; and

Figure 6 is a sectional exploded view showing an alternative form of assembly.

Referring in detail to the illustrative embodiment of my invention shown in the drawing, and turning first to Fig. 4, I have shown an insulating cylindrical core I0 vcomposed advantageously of a molded phenolic condensation product, the core having a cylindrical enlargement IIv at one end and being axially recessed as at I2 (Fig. 3), to house the contact members I3, Il and I5 shown in Fig. 5, as presently described more in detail. A similar insulating disk I6 completes the core III, mating with the core enlargement II, perforated as at I 1 in three separate apertures to permit it to pass over and be retained on the core by the snug fit in said apertures II (Fig. 2) of the integral tails I3a, Ila and I5a oi' the contacts I3, I4 and I5. As later described, the disk I6 also holds the contacts in place.

The Contact members I3, I 4 and I5 are desirably of phosphor bronze, silver plated for enhanced conductivity, and are here shown of square cross-section so that their end terminations are received snugly in square counter recesses I8 in the opposite end of the core, which is closed by the integral wall I9 except where perforated as at 20 in three separate apertures aligned with the apertures Il. Thus the Contact members are held against rotation in the core.

The contact members I 3, I4 and I3 are adapted to interengage with electrode-like members and in this instance are centrally axially bored as at 2I to receive the prongs 22, 23 and 24, the prongs passing through the apertures 20 when appropriately positioned in a manner and by means presently further described.

As best shown in Fig. 5, in accordance with the present invention, one of the contacts, in this instance the contact I3, has riveted thereto as at 25, a metallic grounding clip 26 fixed transversely of the contact member and having its free ends bowed as at 2T. The clip also clamps to the contact member I3 the fork 2l having a pair oi spring fingers 29 lying along and on each side of the contact I3 but angled away from this contact I3 each toward one of the contacts Il and I3 so as to be resiliently pressed against these latter contacts and under certain conditions to make an electrical engagement therewith. In order to break this electrical engagement when the prongs 23 and 2l are inserted in the contacts Il and I5 respectively, these latter parts are arcuately notched as at 30 respectively, in the vicinity of their engagement point with the spring fingers, to have laid across them in the notches 30 the semi-cylindrical cam bar 3I of an insulating phenolic condensation product. The rounded part of the cam bar lies in the notches and when the prongs 23 and 24 are withdrawn is completely received in the notches so that at such time the y rounded face of the cam bar, their ends being tapered as is Awell known, and cam the bar outwardly of the notches 30. The cam bar thus is pressed against the attened extremities 32 of the spring fingers 29 and moves these fingers out of engagement with the contacts I4 and I5, as shown in full lines in Fig. 2. It will be understood that it is contemplated that when the prongs `23 and 24 are received in the contacts I4 and I5 respectively, the prong 22 may be also received in the contact I3, this latter contact being desirably split longitudinally as at 33 to enhance its resilience and improve the electrical engagement between the contact I3 and -the prong 22.

Having described the internal construction of the core I0, the core is assembled, for example with the plug type shell 34, by insertion of the reduced end of the core into the shell from the direction of the slightly enlarged end 35 of the shell until the exterior peripheral shoulder 36on the core abuts the internal annular shoulder 31. "in the'shell, atV which time the enlarged portion II and disk I6 of the coreare received in the .enlarged part35 of .the shell and the closed end clamped thereto as by means of a'clampring 58h. When the plug type shell 34 is then inser-ted into the receptacle type shell 46 and the coupling sleeve 52 tightly screwed onto the screw threads 59 of the shell 46, as at 60, Fig. 2, the core I0 is moved inwardly but non-rotatively so that the prongs 22, 23 and 24 are pushed through the apertures in lthe core and intothe contacts I3, I4 and I5 respectively.

To provide for a single relative rotative engagement of the shells 34 'andv 46, the parts carry interengaging expedients such as the keyway 6I extending longitudinally along the outer surface of the shell 34 from its free end 38 to the annular nange 55 and a corresponding key 62 extending on the inner surface ofthe shell 46 from its free end 63 to its internal shoulder 64 which retains the insulating body 45 therein. This single relativev rotative position of the shells 34 and 46 and t he relative rotative positions of the core I0 and shell 34 and body 45 and shell 46 as determined by the splines 39 and 41, respectively, insures that the wire 65 is in electrical engagement with the wire 66, the wire 61 with the wire 68, and .the wire 69 with the wire 10. Thus, denite polarity is assured. It will be understood that the wires 65, 61 and '68 may be suitably soldered to the tails I3a, I4a, and I5a of the contacts I3, I4 and I5 as at`1I respectively, and, similarly,that the wires 65, 5l

20 of the core is substantially flush with the, open f end 38 of the shell'. To prevent relative rotation between the core and the-shell, the partsmay have rotatively interengaging shoulders. As

here shown, the enlarged end 35 of the shell hasv an internal longitudinal feather 36 and the enlarged part II of the core and the disk I6 are jointly grooved aswat 40 to v.receive the feather 39. At this Vtime the free ends 21 of the ground- -ing clip 26 lie in the cut-outs 4I in the core and press resiliently against the interior surface `of the shell as at 42 makingan electrical grounding engagement therewith.k The core is desirably the'bocly 45 and its auxiliary disk 4% which functions similarly to the disk I6 are similarly held in the shell 46 by one of the spring split rings 43, indentations 49 serving to permit access for` a screw driver or other removing tool to pry out the split rings when desired. The shel146 may have a mounting fiange 50 which may be perforated A as at 5I for passage of .screws for mounting the shell on a panel. y i

For completing a connection, the shell 34 with its housed core I0 has passed thereover the internally'. threaded coupling sleeve 52 knurled as at 53 and having an internal annularshoulder 54 which bears rotatably against the peripheral annular flange 55 on the shell 34 disposed Where the enlarged part 3,5 joins the main part .of the shell 34. Also this enlarged part 35 is externally threaded as at 56. to have screwed thereon fthe nipple 51 which in turn is externally threaded as Vat 5B to have a iiexible metallic conduit 58a and 10 may be suitably soldered to the tails 22a, 23a .and 24a of the prongs 22, 23 and 24 as at 12 respectively.

the other, say the right-hand magneto. The wire 68 may be connected with'the magneto switch terminal for .theleft-'hand magneto and the wire 'VIIIy with the magneto switch terminal for the rightfhand magneto. The ,wire 65 may be grounded, and the wire 66 may be used or not as desired, the device functioning under some conditions with or without the wire y66 and with or without the prong 22. When the connection is made as shown in Fig. 2, and the prongs 23 and 24 are received in the contacts I4 and I5, the spring fingers 2S are insulated from the contacts so as to maintainclosed circuits through wires When, now, the coupling sleeve 52 is unscrewed, the shell 34 is withdrawn from the shell 46 and the circuits 61-68 and AE39-410 Vare thus opened.

Immediately upon opening'of the latter circuits,

the spring fingers29, being no longer heldy out of device will also, as will be seen, function under some conditions without the wire 65.

If it be desired to vrf =werse the assembly, the

, core I0 instead of beingv carried by the shell 34 may be placed in the shell 46, as shown in Fig.

with no change necessary in the construction of the parts, but merely by removing the spring split rings 43, .pulling the core I0 out of the shell 34, and inserting it into the shell 46, from which the insulating body 45 has been removed, the latter being then inserted into the shell 34, whereupon the spring split rings 4.3 are replaced to hold the parts in the new assembly.

It will be understood that when the assembly of Fig. 6 is employed, the grounding path is established through the shell 46 and a metallic panel on which it may be mounted, such as a bulkhead, nre wall, or the like, or through wire 65.

Manifestly, the invention is not limited to details of construction shown for purposes of eX- emplication. Furthermore, it is not essential that all features of the invention be used conjointly, as various combinations and sub-combinations may be advantageously employed.

Such changes may be made as fall within the scope of the following claims without departing from the invention. i

Having described my invention, I claim:

1. In an electrical connector of the class described, the combination with a metallic shell, of an insulating core therein, a. pair of contacts in the core having axial bores therein for receiving prong electrodes, notches in said contacts intersecting said bores, an insulating bar in said notches, said bar being rounded to be cammed by said prongs, a metallic spring clip carried by the core, cut-outs in the core permitting the free ends of the clip to engage the shell, a metallic y fork connected with the clip and having a pair of spring ngers, said spring fingers being engageable with the contacts when the prongs are withdrawn and adapted to be pressed upon by said insulating bar to separate the ngers and contacts when the prongs are inserted.

2. In an electrical connector of the class described, the combination with an insulating core, of a pair of contacts having axial bores therein for receiving prong electrodes, notches in said contacts intersecting said bores, an insulating bar in said notches, said bar being rounded to be cammed by said prongs, a metallic spring clip carried by the core, cut-outs in the core through which the free ends of the spring clip project, a

metallic fork connected with the clip and having a pair of spring ngers, said spring fingers being engageable with the contacts when the prongs are withdrawn and adapted to be pressed upon by said insulating bar to separate the ngers and contacts when the prongs are inserted, whereby the contacts are alternatively in engagement either with the prongs or the lingers.

3. In an electrical connector of the class described, the combination of a pair of contact members having axial bores therein for receiving prong electrodes, notches in said members intersecting said bores, an insulating bar in said notches, said bar being rounded to be cammed by said prongs, a spring nnger engageable with each contact member when the prong is withdrawn and adapted to be pressed upon by said insulating piece to separate the finger and contact member when the prong is inserted, whereby the contact is alternatively automatically in engagement either with the prong or the finger but not both simultaneously.

4. ln an electrical connector of the class de scribed, the combination with an insulating core, of a pair of separated contacts carried thereby for engagement with separable electrodes respectively, a third contact also carried by said core for engagement with an electrode, a grounding connection to said third contact, a pair of metallic spring iingers electrically connected with the third contact and bearing against the pair of first mentioned contacts respectively, and insulating cam means carried by the core between the pair ci first mentioned contacts and said spring fingers and actuated by interengagement of the said rst mentioned contacts and the elec trodes to abut the spring fingers and move them into position-insulated from the said rst mentioned contacts, whereby when said electrodes are removed the said rst mentioned contacts are also grounded through said grounding connection by engagement with said spring iingers.

ARTHUR, J. SCHMITT. 

